Paul, the ArduinoModbus library has been working great on a Teensy 3.1 board, until I tripped on the USB programming cable and ripped the microUSB connecter off the board. Note to self: tidy up my hobby room.
I decided to take the opportunity to move the project to a Teensy 3.5, using Serial5 instead of Serial1. That's where things have gone off the rails. I initially thought I'd made a wiring error but have confirmed good comms using the modified serialPassthrough sketch below:
Code:
void setup() {
Serial.begin(9600);
Serial5.begin(9600);
Serial5.transmitterEnable(35);
}
void loop() {
if (Serial.available()) { // If anything comes in Serial (USB),
Serial5.write(Serial.read()); // read it and send it out Serial1 (pins 0 & 1)
}
if (Serial5.available()) { // If anything comes in Serial1 (pins 0 & 1)
Serial.print(Serial5.read(),HEX); // read it and send it out Serial (USB)
Serial.print(" ");
}
}Modbus Master UART and resulting Serial Monitor traffic:
But when I try the stripped down Modbus Slave sketch below, the Master times out.
Code:
#define RS485_DEFAULT_TX_PIN 33
#define RS485_SERIAL_PORT Serial5
#define CUSTOM_RS485_DEFAULT_DE_PIN 35
#define CUSTOM_RS485_DEFAULT_RE_PIN -1
#define debug
#include <ArduinoRS485.h> // ArduinoModbus depends on the ArduinoRS485 library
#include <ArduinoModbus.h>
const int numCoils = 5;
const int numDiscreteInputs = 5;
const int numHoldingRegisters = 20;
const int numInputRegisters = 5;
void setup() {
Serial.begin(115200);
// while (!Serial) ; // Needed for Leonardo only MAY NEED TO DELETE FOR TEENSY
Serial5.begin(9600);
Serial5.transmitterEnable(35); // specific to teensy
// start the Modbus RTU server, with (slave) id 1
if (!ModbusRTUServer.begin(1, 9600)) {
Serial.println("Failed to start Modbus RTU Server!");
while (1);
}
// configure registers at starting address 0x00
ModbusRTUServer.configureCoils(0x00, numCoils);
ModbusRTUServer.configureDiscreteInputs(0x00, numDiscreteInputs);
ModbusRTUServer.configureHoldingRegisters(0x00, numHoldingRegisters);
ModbusRTUServer.configureInputRegisters(0x00, numInputRegisters);
ModbusRTUServer.holdingRegisterWrite(5,1); // set initial display
}
void loop() {
// poll for Modbus RTU requests
if(ModbusRTUServer.poll()) updateRegs();
} // Loop
// function to tie sketch variables to registers
void updateRegs() {
#ifdef debug
Serial.print("Coils:");
for (byte i=0; i<numCoils; i++) {
Serial.print(i); Serial.print(":"); Serial.print(ModbusRTUServer.coilRead(i),HEX); Serial.print(", ");
}
Serial.println();
Serial.print("DI's:");
for (byte i=0; i<numDiscreteInputs; i++) {
Serial.print(i); Serial.print(":"); Serial.print(ModbusRTUServer.discreteInputRead(i),HEX); Serial.print(", ");
}
Serial.println();
Serial.print("Holding Regs:");
for (byte i=0; i<numHoldingRegisters; i++) {
Serial.print(i); Serial.print(":"); Serial.print(ModbusRTUServer.holdingRegisterRead(i),HEX); Serial.print(", ");
}
Serial.println();
Serial.print("II's:");
for (byte i=0; i<numInputRegisters; i++) {
Serial.print(i); Serial.print(":"); Serial.print(ModbusRTUServer.inputRegisterRead(i),HEX); Serial.print(", ");
}
Serial.println();
Serial.printf("%02d:%02d:%02d ",lowByte(ModbusRTUServer.holdingRegisterRead(2)),highByte(ModbusRTUServer.holdingRegisterRead(3)),lowByte(ModbusRTUServer.holdingRegisterRead(3)));
Serial.printf("%02d/%02d/%02d, ",highByte(ModbusRTUServer.holdingRegisterRead(1)),lowByte(ModbusRTUServer.holdingRegisterRead(1)),lowByte(ModbusRTUServer.holdingRegisterRead(0)));
#endif
}The one key difference is I'm attempting to now use Serial5 on the 3.5 instead of Serial1 on the 3.1 so my best guess is one of the cascaded libraries does not correctly handle Serial5? Any insight would be greatly appreciated!